Power transmission



Feb. 25, 1930.

Filed Oct. 16, 1925 B. CHALMERS 1,748,108

POWER TRANSMI SS ION 2 Sheets-Sheet 1 Feb. 25, 1930- H. B. CHALMERS 1,743,108

POWER TRANSMISSION Filed on. 16. 1925 -2 Shets-Sheet 2 Patented Feb. 25, 1930 1,748,108

UNITED STATES PATENT OFFICE ma 3. onezmnns, or NEW YORK, N. Y.

POWER TRANSMISSION Application filed October 16, 1925. Serial No. 62,756.

. One object of my invention is to provide cerned. As the shaft is rotated, the arm mechanism by which the transmitted speed rotates wit it and the mass 8 is compelled to varies substantially inversely with the load rotate about the center of the axis 5 in a path at operating speeds. I whose direction is controlled by the track 9.

5 othenobject is to obtain an approximate- In the preferred form, approximately twoiv uniform torque on the driven member thirds of the track is substantially an involute t roughout all the varying relative positions curve so that while the mass 8 rotates about of driving and driven shafts. the axis 5, it is gradually forced toward the Another object. is to provide mechanism axis by the decreasing radius of the involute,

l0 embodying as fewparts and as simple as and its velocity is, during this period, gradupossible for eifectingthese results. ally decreased from a maximum to a mini- Another object is to avoid vibration as mum. During this portion of the travel cenmuch as possible. trifugal force transmits a clockwise torque Such devices have many uses, such as trans to the driven member.

5 mission mechanism for motor vehicles, elec- The linear velocity of the mass 8, of course, tric motor drive, the application to punch and tends to remain constant but its action is shearing processes, lathes, and for machine constrained not only by the surface of the tools. In fact the .invention is not limited cam 9 but by the links 10 and 11. If we assume to any particular art other than power transthe angular velocity of the crank arm 10 to 0 mission in general. be constant, the mass 8 will be guided toward In the accompanying two sheets of drawand from the center of the shaft 5 as the arm ings, I have illustrated the principles of the rotates. As the mass decreases its distance invention as embodied in one form of mechafrom the center it must increase its angular nism and have diagrammatically illustrated. velocity about that center in order to 5 the general theory of operation. maintain its constant linear speed. This in- Figs. 1 and2 are diagrammatic views showcrease in angular velocity is retarded by the ing the outline of the elements of the invenlink 10 which is revolving at a constant angution with lines indicating the relative movelar velocity. The mass 8 is therefore pushing ments of the parts. on the link 10 instead of being drawn by it. 30 Fig. 3 is an end view of one form of mecha-- This produces compression in the link 11. nism embodying my invention. This compression in the link 11 continues- Fig. 4 is a'plan view and partial section of from the longest to the shortest radius of the the same. involute groove, dur ng which time kinetic Driving and driven members 5 and 6 reenergy of the mass is being given up or re- 35 .spectively are in alignment. turned to the driving arm or motor.

A casing or frame 7 may be employed to Kinetic energ of the mass is being reduced enclose the parts and may constitute a part, and given up tirough a compression in the of the driven member. link 11, and a pressure against the track sur- In Figs. 1 and 2 I have shown diagramface, also giving a clockwise torque to the matically a mass or body 8 representing one driven member during this period of the or more of such masses to which motion is revolution. If the driven member at this given by.the driving member and which is time is locked or stationary, substantially all regulated and constrained by a cam-like track of the difference between the kinetic energy indicated bythe curved line 9, carried by the at its maximum and minimum point is re- 45 driven member. The mass is connected to the turned to or re-absorbed by the driving memdriving member by an arm 10 andlink 11 her or motor. The remainder of the track, which is hinged to the outer end of the arm. in this case approximately one-third of its The link 11, of course, constitutes a part of time of contact with the roller, is so designed the mass8 or with substantially the same as to bring the mass 8 back to its original efiect so far as its effect in transmission is conposition, direction of travel, and velocity. 1

The natural path of the hinged mass 8 during this period is controlled by its acceleration and consequent increasing kinetic energy balancing the centrifugal pull which would bring the mass 8 bac to the involute curve much later than is desired and in a direction crossing said involute. The track is, therefore, designed to constrain the mass so that the centrifugal force is over-balanced by the inertia or resistance to acceleration to the extent that there is a continuous clockwise torque on thetrack and the Weightmeets the involute tangentially. During this portion of the revolution of the mass, its velocity is being increased, hence its kinetic energy is being increased, with a resulting heavy tension in the link 11, and the power is again withdrawn from the engine.

When the driven shaft is allowed to rotate, the acceleration and retardation of the mass become less because there is a greater time interval between the maximum and minimum velocities. For instance, if the driving shaft is running 1000 R. P. M. and the driven shaft is still, the velocity of the mass will pass from the maximum velocity tothe minimum velocity and back 1000 times per minute, whereas with the driving shaft at 1000 R. P. M. and the driven shaft at 600 R. P. M. the mass will pass from maximum to minimum velocity and back only 400 times in a minute.

The difference in tion between the slowest and fastest points, and vice versa, and consequently the tension and compression in the links 11 is less when the driven shaft rotates, thus transmitting the same power from 'the driving to the driven member but less torque. The torque becomes less and. less as the speed of the driven member approaches the speed of the driving member.

In the form shown in Figs. 3 and 4 the casing 7 which is a part of the driven member 6 is formed of two parts bolted together at 12. The driving member 5 passes through one side of the casing 7 and has a bearing at 13 in the opposite side.

There are in this form three masses 8 hinged to the rotating driver 10. Each mass includes the guide rollers 14 which travel outside and inside of the track 9. The track is shaped so that the masses 8 are alternately accelerated and retarded as the driving member is rotated. When one mass is absorbing energy the others are giving up the stored energy. This produces a substantially uniform torque on the driven member throughout each revolution.

Any number of masses 8 may be used.

The track 9 is preferably designed to give an acceleration and decelleration of each mass 8 at each revolution but the track may 'be shaped to produce two or more cycles of alternate acceleration and decelleration if dea substantially uni-directional acceleration and retarda- I I have shown two tracks 9 one on each side of the casing 7 so as to more uniformly balance the stresses. f

. I also contemplate that other changes may be made within the scope of my claims.

I claim: I

1'. Power transmission apparatus comprising a driving member, an arm driven thereby, a mass hinged to said arm, a driven member, a' track connected thereto for controlling the direction of movement of said mass, said track having an involute surface extending through a part of its circumference and a connecting curve shaped so that the inertia where fpullin oppositely overbalances the centri ugal orce so as to cause torque on the driven member.

. 2. Power transmission apparatus comprising a driving member, an arm driven thereby, a mass hinged to said arm, a driven member, a track rotatable therewith, rollers carried by said mass and engaging said track for controlling the direction of movement of said mass, said track h'aving its active surface shaped as a substantially involute curve with a connecting curve of a variable radius to cause a substantially uni-directional torque on the driven member throughout a complete revolution; 1

3. Power transmission apparatus comprising a driving member, an arm driven thereby, a mass hinged to said arm, a driven member having two tracks facing toward each other, rollers carried by said mass and entially involute curve with a connecting curve of a variable radius to cause a substantially uni-directional torque on the driven member, said mass being mounted between said tracks.

4. Power transmission apparatus comprising a driving member, a driven memberhaving a casing with two tracks, spaced apart from each other, each track having an involute curved portion with a connecting curve of a variable radius,- and a mass guided by said tracks and driven by said driving member. I

5. Power transmission apparatus comprising, a driving member, arms driven thereby, a mass hingedto each arm,'a driven member, a track connected thereto for controlling the direction of movement of all of said masses, said track havingits active surface shaped to cause a substantially even uni-directional torque on the driven member throughout most of a complete revolution, said track having an involute surface extending throughout a part of its circumference, and a connecting curve shaped so that the inertia at a 'ven point at least partially counteracts the orce, tending to move the mass outward- 1y from the axis of the apparatus.

said track 6. Poyver transmission apparatus comprisng a drivmg member, a driven member havmg a casing with a curved gulde track, the

said track having an mvolute curved portion with a concave-convex connecting curved wall of a variable radius and a mass guided by said track and driven by said driving member, theshape of said track being such as to produce a substantially unidirectional m torque on the driven member throughout the gi'eater part of the complete revolution there- HARRY B. OHALMERS. 

